1. Field of the Invention
This invention relates to an optical disk, an optical disk recording method, and an optical disk recording apparatus, and more particularly to a method of recording data onto a recordable optical disk.
2. Description of the Related Art
In recent years, DVDs (Digital Versatile Disks) have been put to practical use in the form of large-capacity optical disks. Recordable DVD-R, rewritable DVD-RW, and DVD-RAM have been standardized as recordable DVDs. Once data is recorded onto a recordable disk, the recorded part cannot be rewritten. A conventional recordable DVD includes a PCA (Power Calibration Area), an RMA (Recording Management Area), and a data recording area DA (Data Area), beginning at the inner periphery in that order. In the data recording area DA, an actual recording process is carried out (refer to, for example, Jpn. Pat. Appln. KOKAI Publication No. 2002-245625, paragraphs [0041] to [0052], and FIG. 1).
The data recording area DA includes a lead-in area where recording parameter data and the like to be read in reproducing the recording data recorded in a data area explained later is recorded, a data area where the recording data is recorded, and a lead-out area where termination data and the like to be read in completing the reproduction of the recording data recorded in the data area. The lead-in area is an area into which recording parameter data and the like are recorded before data is recorded into the data area. The lead-out area is an area into which termination data is recorded before the recording of recording data onto the entire DVD is completed. The capacity of each area is predetermined and cannot be changed.
When data is recorded onto such a DVD (assuming that recording is done, beginning at the inner periphery of the data area), test recording is first performed in the PCA area. The reason is that the parameters (including intensity and pulse width) of the recording waveform in recording data onto the optical disk are adjusted on the basis of the result of the test recording, since even optical disks of the same type differ in characteristic from manufacturer to manufacturer or in recording waveform according to the temperature in the use environment, the laser operating environment, or the like.
Thereafter, management data and user data are recorded into the RMA area and the data area, respectively. The management data includes data indicating which part of the data area has been recorded into (how much of the data area has been recorded into). The management data is updated to the latest one according to how much user data has been recorded. Once data is recorded onto a recordable DVD, the recorded part cannot be rewritten. Therefore, each time the management data is updated, the remaining capacity of the RMA area decreases. Depending on the way the management data is updated, the unrecorded part of the RMA area can run out before all of the data area has been recorded into. When the RMA area has run out of the unrecorded part, the management data cannot be updated. Therefore, the recording of the data area has to be stopped.
As described above, in the DVD apparatus, the recording waveform changes according to temperature change or variation with time. In addition, the optimum recording waveform changes according to the recording position of the disk. To adjust the recording waveform according to these changes, the DVD apparatus performs test recording in the PCA area, thereby adjusting the parameters of the recording waveform. As when the management data is updated, each time test recording is performed, the remaining capacity of the PCA area decreases. Depending on the way test recording is performed, the unrecorded part of the PCA area can run out before all of the data area has been recorded into. When the PCA area has run out of the unrecorded part, the recording operation has to be stopped or the user data and management data have to be recorded without adjusting the recording waveform. From the part where recording has been performed using the unadjusted recording waveform, sufficiently reliable data cannot be reproduced.
To prevent the PMA area or the PCA area from running short, securing a larger capacity of the RMA area or the PCA area beforehand can be considered. In this case, however, the capacity of the data area decreases. As a result, even though the unrecorded part remains sufficiently in the RMA area or the PCA area, the capacity of the data area may run short.
As described above, in the conventional recordable optical disk, because of shortage of the capacity of the RMA area or the PCA area, a part of the user data to be recorded cannot be recorded. Even if the user data can be recorded, it cannot be reproduced with sufficiently high reliability. To overcome this problem, a larger capacity of the RMA area or the PCA area could be secured in advance, causing another problem: the capacity of the user data zone runs short.